Rolling of slabs



w. BAYER 3,425,254

ROLLING 0F SLABS Filed March 3, 1964 Feb. 4, 1969 Inventor: A/flfi'f' 547(c- MM,

64;; Alumey,

United States Patent M 56,114 US. Cl. 72-198 Int. Cl. B21d l/02; B21b 41/02, 1/08 4 Claims The invention relates to the rolling of slabs into blocks of substantially square cross-section, and relates more particularly to methods of and means for carrying out the aforesaid purpose at fewer rolling passes and hence greater economy as compared to the present rolling practice.

Slabs are usually used as primary material for producing plate bars, sheet metal, or metal bands. For creating semifinished products to be worked subsequently on forming roll trains however, one normally prefers blocks of square cross-section.

It has been proposed to use slabs of suitable metric weight, made in a continuous casting process, as primary material for the production of heavy semifinished products for use in connection with medium and forming roll trains. The rolling can take place in plain rolls, as well as in suitably grooved bloomer rolls. In connection with slabs of a large ratio of width to thickness, however, it has been experienced that these slabs when they are rolled on end upset, namely positioned during rolling with their width upright, bulge out on their side surfaces nonuniformly, namely much stronger at a point closest to the point of contact with the rolls. It is only when the upright width of the slab comes down to a height of from 350 mm. (13.78 in.) to 300 mm. (11.82 in.), that the bulge becomes noticeable about midway of the width.

It is accordingly among the principal objects of the invention to provide methods of and means for rolling slabs on end upset in such a manner that their side bulging will include substantially uniform bulging which comprises bulging midway of their width.

It is a further object of the invention to reduce the number of rolling passes needed for rolling slabs into blocks of substantially square cross-section.

It is a still further object of the invention to carry out such rolling with specially profiled rolling faces, including grooved and flat portions, passed in specific sequence.

Further objects and advantages of the invention will be set forth in part in the following specification and in part will be obvious therefrom without being specifically referred to, the same being realized and attained as pointed out in the claims hereof.

With the above and other objects of the invention in view, the invention consists in the novel methods, construction, arrangement and combination of various devices, elements and parts, as set forth in the claims hereof, one embodiment of the same being illustrated in the accompanying drawings and described in the specification.

In the accompanying drawings, the single view is a fragmentary schematic elevational view, partly in section, of a grooved bloomer roll pair in accordance with the invention.

There is provided a roll 1 which forms a part of a roll train in which there is a second symmetrically built counterroll that cooperates with the roll 1.

The roll 1 has a first groove A, a second groove B and a flat roll portion C. The aforesaid counterroll of the roll train will have symmetrically arranged with the roll 1 appropriate grooves A and B and flat roll portions 'nce C; the grooves A and B of the two rolls complete the respective upset passes, and the flat portions C complete the flat rolling pass.

It will be understood that while all the roll portions A, B and C are shown on the same roll 1, they may instead be formed on different rolls. The instant showing merely simplifies the explanation, and also illustrates a preferred embodiment.

In order to carry out the upset squeezing most efficiently, the slab is being passed during each upset thrust through a pass formed by the grooves shown at A and B, each of which has an internal central annular ridge that projects radially from the groove base. Thus, the slab is first passed through the groove A which has a central annular internal ridge 3 that projects radially towards the groove opening from the base 2. The side surfaces 4 of the groove A form an angle with each other (which is larger than the groove angle usually found with bloomer rolls now in used).

This angle is about 8.

Also, the depth of the groove A is greater than that found in grooves of bloomer rolls now in use.

During the aforesaid first upset thrust, the slab is positioned with its width upright so that the narrower surfaces will form the top and bottom faces of the slab. The ridge 3 will engage the central face section of the slab and will exert thereon a compressive force that is larger than the compressive force exerted on the side sections of the slab face.

During the second upset thrust, the slab is in the same position through the groove B as it had been through the groove A. The depth of the groove B, however, is smaller than that of the groove A, and the radial height of the central ridge 5 is smaller than that of the ridge 3. As best shown in the drawing, the convex summit of the ridge 3 in the groove A is spaced from the surface of the roll 1 for a distance smaller than that of the ridge Sin the groove B.

The angle formed between the side surfaces 6 of the groove B is approximately the same as that formed between the side surfaces 4 of the groove A.

Upon the completion of the rolling through the groove B, the slab will bulge out at its side surfaces substantially uniformly throughout its width.

The flat rolling section C is, for the purpose of convenience and preference, and not in any limiting sense, shown adjacent the groove B, and serves to exert pressure against the bulge when the slab is passed through the pass formed by the flat rolling portions of the cooperat ing rolls of the roll train, with the slab turned for onequarter of one turn as compared to its previous position, so that the bulging sides face the rolling surfaces, for equalizing.

Example In the rolling schedule shown on the table below, there is indicated the sequence of steps for rolling a slab, for example of an initial size of 1000 mm. (39.37 in.) by 250 mm. (9.84 in.) down to a shaped bloom of the size of 300 mm. (11.81 in.) by 250 mm. (9.84 in.). The width of the slab is designated h, and the thickness is indicated b. In the columns Ah and Ab there are given the dilferences in width and, respectively, increase in thickness between the individual rolling thrusts.

The first two columns of the table indicate the number of thrusts and the grooves (A, B or C) used.

From the table it can be ascertained that rolling is first carried out with the grooves A. The specific shape of the groove A described in the foregoing causes a substantial decrease in width of the slab, and correspondingly a strong pressure which is passed on down to the center of the roller slab, so that even at large widths there is obtained an outward bulging.

Owing to the configuration Of the groove A, the pressure will not only be at right angle to the roll axis, but also at various angles to the vertical; as the groove A is wider than the rolling grooves of bloomer rolls now in use, the groove A owing to the aforesaid pressure distribution will be filled even near the contact surfaces of the roll; during the ensuing thrust of the slab through the groove B, there will be achieved a further increase in thickness up to the size of the groove B.

The method and apparatus described in the foregoing brings about the following beneficial results: The bulging out of the slabs will start earlier during the succession of rolling steps, at larger slab widths, and towards the end of the succession of rolling steps will result in a larger increase in width throughout the entire cross-section, than has heretofore been possible with normal bloomer roll grooves.

The second thrust or pass takes place in the groove B, which to a certain extent eliminates any excessive surface impression that had been imparted to the slab in the preceding thrust through the groove A.

Subsequently the slab is, in an equalizing thrust, rolled by the fiat rolling portions C of the rolls.

ROLLING SCHED ULE Slab width Slab thick- Ah Ab Thrust Pass h in mm. ness 1) in mm. in mm. N0. (grooves) (inches) in mm. (inches) (inches) (inches) Turn the work piece turn Turn the work piece (10.24) (30. 71) 12) 4 C Idle return Turn the work piece Turn the work piece (10. 63) (22.05) 12) 8 C Idle return Turn the work piece (11.10) (11. 89) (2.67) 75) 12 C Idle return Turn the work piece Certain of the advantages of the invention have already been herein referred to. It may be useful, however, to allude particularly at this point to the great savings in the reduced number of thrusts afforded by the instant invention, as compared to the thrusts needed with normal roll grooves that are free from any internal ridge. By this reduction in the number of thrusts required for a given reduction in size, the efiiciency of the rolling mill is correspondingly increased.

I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

Having thus described the invention, what I claim as new and desire to be secured by Letters Patent is as follows:

1. In a method of rolling, with the aid of grooved bloomer rolls, slabs into blocks of substantially square cross-section, the step comprising first rolling through one groove, each elongated slab positioned with its Width upright so that the narrower surfaces will form the top and bottom faces of the slab while engaging the central face section of the slab with an annular raised first ridge projecting radially in said one groove from the groove base for a first height, thereafter rolling each slab in the same position through a second groove while engaging the central face section with an annular raised second ridge projecting radially in said other groove from the groove base for a second height, said first height of said first ridge projecting from the groove base being considerably larger than the second height of said second ridge.

2. In a method of rolling slabs, as claimed in claim 1, thereafter rolling, for equalizing, with said flat rolling portions said slab so positioned that its side surfaces form the top and bottom.

3. In a roll train, for use in rolling slabs into blocks of substantially square cross-section, the combination of opposite grooved bloomer rolls each roll having portions with upset grooves and a fiat rolling portion, each groove comprising an internal central annular ridge projecting radially from the groove base for a height, a first of said grooves having a first depth and a first ridge, a second of said grooves having a second depth which is smaller than the first depth and having a radial height of ridge projection from the base which is smaller than that of said first ridge, whereby an elongated slab first being rolled through said first groove and thereafter through said second groove, with the slab width upright, will engage with its narrow face first the first ridge in the first groove and thereafter the second ridge in the second groove.

4. A roll, for use in a roll train, having two upset grooves and a flat rolling portion, each upset groove comprising an internal central annular ridge projecting radially for a height from the groove base, the depth, and the height of the ridge projecting from the groove base, of the first groove being larger than the depth, and the height of the ridge projecting from the groove base, respectively, of said second groove.

References Cited UNITED STATES PATENTS 318,220 5/1885 Taylor et al. 22366 1,425,971 8/1922 Johns 72365 1,826,622 10/1931 Longnecker 72-231 FOREIGN PATENTS 14,837 6/1897 Great Britain.

RICHARD J. HERBST, Primary Examiner. 

1. IN A METHOD OF ROLLING, WITH THE AID OF GROOVED BLOOMER ROLLS, SLABS INTO BLOCKS OF SUBSTANTIALLY SQUARE CROSS-SECTION, THE STEP COMPRISING FIRST ROLLING THROUGH ONE GROOVE, EACH ELONGATED SLAB POSITIONED WITH ITS WIDTH UPRIGHT SO THAT THE NARROWER SURFACES WILL FORM THE TOP AND BOTTOM FACES OF THE SLAB WHILE ENGAGING THE CENTRAL FACE SECTION OF THE SLAB WITH AN ANNULAR RAISED FIRST RIDGE PROJECTING RADIALLY IN SAID ONE GROOVE FROM THE GROOVE BASE FOR A FIRST HEIGHT, THEREAFTER ROLLING EACH SLAB IN THE SAME POSITION THROUGH A SECOND GROOVE WHILE ENGAGING THE CENTRAL FACE SECTION WITH AN ANNULAR RAISED SECOND RIDGE PROJECTING RADIALLY IN SAID OTHER GROOVE FROM THE GROOVE BASE FOR THE SECOND HEIGHT, SAID FIRST HEIGHT OF SAID FIRST RIDGE PROJECTING FROM THE GROOVE BASE BEING CONSIDERABLY LARGER THAN THE SECOND HEIGHT OF SAID SECOND RIDGE. 